Bosch GSB 21-2 Professional Notice Originale page 24

24 | English
Switching On and Off
To start the machine, press the On/Off switch 8
and keep it pressed.
To lock the pressed On/Off switch 8, press the
lock-on button 6.
To switch off the machine, release the On/Off
switch 8 or when it is locked with the lock-on
button 6, briefly press the On/Off switch 8 and
then release it.
Safety Clutch
To limit dangerous reaction
torque, the machine is
equipped with a safety clutch
(anti-rotation).
If the tool insert becomes caught or
jammed, the drive to the drill spindle is in-
terrupted. Because of the forces that occur,
always hold the power tool firmly with both
hands and provide for a secure stance.
If the power tool jams, switch the machine
off and loosen the tool insert. When switch-
ing the machine on with the drilling tool
jammed, high reaction torques can occur.
Adjusting the Speed/Impact Frequency
The speed/impact rate of the switched on pow-
er tool can be variably adjusted, depending on
how far the On/Off switch 8 is pressed.
Light pressure on the On/Off switch 8 results in
low speed/impact rate. Further pressure on the
switch increases the speed/impact rate.
Preselecting the Speed/Impact Frequency
With the thumbwheel for speed preselection 9,
the required speed/impact frequency can be
preselected even during operation.
The required speed/impact frequency depends
on the material and the working conditions, and
can be determined through practical testing.
2 609 932 659 | (4.2.09)
Electronic Speed Preselection (GSB 21-2 RCT)
With the thumbwheel for electronic speed
preselection 3, the required speed/impact fre-
quency can be selected even if the machine is
running.
The required speed/impact frequency depends
on the material and the working conditions, and
can be determined through practical testing.
Constant Electronic Control (GSB 21-2 RCT)
The constant electronic control keeps the prese-
lected speed and impact rate nearly constant
between no-load and load conditions.
Electronic Torque Limitation/Speed Preselec-
tion (Torque Control) (GSB 21-2 RCT)
Drilling with speed preselection:
Set the selector switch 4 to the
"Drilling" symbol. The required
speed can be selected with the
thumbwheel 3; it can also be adjust-
ed during operation.
Screwdriving with torque limita-
tion: Set the selector switch 4 to the
"Screwdriving" symbol. The effec-
tive torque at the drill spindle can be
variable adjusted with the thum-
bwheel 3 during operation:
I=low torque, III=high torque.
The maximum speed is automatically adapted to
the adjusted torque.
If the preselected torque is reached during
screwdriving, the machine switches off; the
drilling tool no longer rotates. If the load on the
machine is then removed with the On/Off
switch 8 still pressed, the drilling tool continues
to run only at very low speed for safety reasons.
After briefly releasing the On/Off switch 8, the
next screw can be driven in with the same
torque.
For screwdriving without torque
limitation, turn the thumbwheel 3 to
the right stop. This setting is re-
quired, when the torque in
position III is not sufficient.
Bosch Power Tools